What causes those adorable dimples in people's cheeks? A terrible muscular deficiency. That's right — every time someone smiles and shows off dimples, they're actually revealing their ultimate weakness. Or a little genetic quirk. Whichever.

Dimples are especially common in the face, because the muscles pull the skin on the face around, instead of just pulling around bones. The face also has bits of body fat, which cause the dimples to be more visible. Most cheek dimples are the result of a shortened muscle, zygomaticus major, pulling on the skin. There are dimples in the chin and the elbows, as well. At rest, it's not noticeable, but as the muscles around it pull into a smile, its shortness creates divots in the face.

What can you do if you have this terrible weakness? All muscles in the body stretch out, if consistently pulled over time. Just as you can stretch a muscle in your leg to make it capable of greater movement over time, you can stretch a cheek muscle or two. Some people do lose their dimples as they grow into adulthood — they lose fat in their face, and their muscles pull longer. But don't play it safe! Identify this culprit, and stretch without mercy. Only then can you smile from a position of total strength.